Pneumatic bicycle-brake



Nu. 6l4,899. Patented Nov. 29, I898. C. SEARS.

"PNEUMATIC BICYCLE BRAKE.

(Application filed Jan. 23, 1897.)

(No Model.)

INVENTOR.

THE Nam-n5 PETERS co. womuruouwunmoms. n 0v UNITED TATES CHARLES SEARS, OF CLEVELAND, OHIO.

PN EU IVIATIC BICYCLE-BRAKE.

SPECIFICATION forming part of Letters Patent No. 614,899, dated November 29, 1898.

Application filed January 29, 1897. Serial No. 621,253. (No model.)

To all whom it may concern:

Be it known that 1, CHARLES SEARS, a citizen of the United States, residing at Cleveland, in the county of Ouyahoga and State of Ohio, have invented certain new and useful Improvements in Bicycles; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to improvements in bicycles and it appertains more especially to the features hereinafter set forth in the an nexed claims.

The object of my invention is to provide a brake of pneumatic order which shall effectually stop a wheel or gently retard its motion without recourse to any mechanical brake, levers, &c.; also, to form a brake with the least number of parts which shall have enough of elasticity to not throw the rider if it is applied very suddenly.

I illustrate my invention in the accompanying drawings, in which Figure 1 shows the relative positions of the pump and controllingvalve as they are placed upon an ordinary bicycle. Fig. 2 is a section through the pump. Fig. 3 is a plan View of the valve in section. Fig. 4 is an elevation of the valve and casing in section. Fig. 5 is a plan View of a graduated valve-port. Fig. 6 is an elevation in section of Fig. 5, showing the valve-port in relation to the valve-casing. Fig. 7 is a detail view showing the devices for holding the valve in position.

I fasten to the bicycle-frame a cylinder A in any suitable manner. Within the cylinder is a piston B, connected to the driving mechanism of the bicycle-in the present instance shown as an eccentric b and strap 1) of the usual order. The eccentric-strap b is connected to the piston B by piston-rod 17 which slides through the removable head 11 On the outside of this head is placed stuffingbox 12 The cylinder A has two openings at, one leading from each end thereof. From these openings tubes a lead to a controlling-valve a placed within the reach of the rider. The Valve a comprises the usual body portion a connected to the handle-bar a by stem o The portion a has grooves it formed therein,

as shown in Figs. 4,5, and 6; These connect with the tubes a and air-ports aZwhich lead to the atmosphere. The handle has a spring a which snubs into notches in the valve-casing, so .as to enable the rider to tell by sense of touch when the valve has reached a predetermined position. This feature,however, is not necessary to the working of my brake. The valve a is suitably secured to the frame of the wheel within easy reach of the rider.

In Figs. 5 and 6 is shown a graduated valveport which will enable the rider to slowly or partially close the valve, as when descending long grades, &c. The two Valve-ports a are practically duplicates of each other, so that the same action takes place at eachport with respect to its tube and its respective cylinder end. By a single movement of the valvehandle a when the val ve-handle is placed so that the tubes a are entirely closed then the maximum braking effect is produced. This, though applied suddenly, is sufficiently elastic to not unseat the rider.

The action of my brake is to apply a retarding effect at each end of the stroke of the piston B, varying more or less, according to the position of the valve-handle a without the necessity of using inlet or outlet valves at the pump. When the valve C62 is entirely closed, the pump will compress the inclosed air atone end of the cylinder, and upon reversing its direction the air which was compressed will expand again and the air at the other end of the cylinder will be compressed, and vice versa, the air being alternately compressed and expanded, these steps continuing to a maximum degree so long as the valve a is entirely closed and to a modified degree if the valve is partially closed, no action whatever taking place while the valve remains entirely open.

If the valve is closed and remains closed, the air at one end of the cylinder will be compressed, while that at the other end will be expanded, and when the reverse stroke takes place the air previously compressed will be expanded with equal force less the energy lost by radiation of heat in compressing, and that portion of air previously expanded will be compressed. This order of events will not add materially to braking efiort upon the mo tion of the machine; but when the rider, keeping time with the right-and-left pedal movement, closes the valve as the pedal moves down and opens it as it reaches its bottom position for a moment to let in free air and allow the compressed air to escape and immediately close it again a new condition will be present which will give as much retardation as the original movement. A few alternate operations of the valve in time With the pump-action will be sufficient to stop the Wheel.

hat I claim is- 1. A brake consisting of a cylinder, a piston therein adapted to be connected with a driving mechanism, two tubes communicatingwwith said cylinder, one at each side of the piston, a valve-casing with which the other ends of said tubes communicate, and valves in the casing adapted to move together in the same direction whereby to simultaneously open or close said tubes and confine or release the air simultaneously on both sides of the piston.

2. The combination with a bicycle-frame, driving mechanism, and Wheels, of a cylinder carried by the frame, a piston in said cylinder connected with some rotating part of the machine, a valve-casing also carried by the machine, two tubes, one of which extends from each end of the cylinder to a corresponding end of the valve casing, and a double valve in the casing operating to simultaneously open or close said tubes whereby to confine or release the air on both sides of the piston in the cylinder.

In testimony whereof I aiiix my signature in presence of two Witnesses.

CHARLES SEARS.

W'itnesses:

D. M. BADER, H. P. SEARS. 

